It is well know to form corrugated strips for use in various devices such as the fins of heat exchangers by moving a flat strip continuously between forming rolls and thereafter through packing rolls to a cutting position, interrupting the movement momentarily at the cutting station and cutting a predetermined length of web from the strip. If the length of corrugated strip is not precisely controlled, the cutting may occur along portions other then the apices which connect the strip. The resultant edge is flawed, makes it difficult to handle the strip. In addition, such an edge can adversely affect the positioning of the strip in the device in which it is to be used.
The problem of cutting such strips is made more complex because of the differences in characteristics of materials. For example, some materials inherently remain in the formed position while others are readily deformed. This affects the spacing of the number of corrugations in any unit length. Specifically corrugations of aluminum tend to return to their original configuration and spacing if spread in longitudinal direction of the web. Copper, on the other hand, must be handled carefully since it does not tend to return to original configuration and spacing. The problem is further complicated by the fact that the spacing of the corrugations may be such that it is difficult to move a cutter into position for cutting at the apex the corrugation.
Accordingly among the objectives of the present invention to provide a method and apparatus for ensuring that the strip will be cut along an apex; which method and apparatus is simple, reliable and can be precisely accurately controlled.
In accordance with the invention, a method and apparatus for cutting corrugated webs from a strip which is continuously formed to define transverse undulating fins or corrugations comprises periodically interrupting the movement of the corrugated strip, spreading a corrugation in the direction of the longitudinal axis of the strip and severing the corrugation at the spread corrugation and the apex of the corrugation. More specifically the corrugated strip is interrupted, adjacent corrugations are moved longitudinal relative one another to locate the corrugation to be cut and a cutter is moved between the adjacent apices to cut the connecting oppositely disposed apex. In one form adjacent apices are engaged and spread apart. In another form, a finger engages a side of a corrugation to position the corrugation to be cut.